|usually yes... It's typically a combination of the Function key (bottom left on an Acer) and a dual-assigned key - typically an arrow key (bottom right on a typical keyboard...).|
The legend Function (or F) on its key will be likely coloured blue. And the brightness "key" will also be a symbol that is blue - and usually looks like a symbol for the sun... There will be two of them - one for increasing and one for decreasing...
Have you per chance checked in the manual for more on this as well?
What model HP do you have?